Hi ! I discover the ODrive thanks to this video performed by this Gentleman.
https://www.youtube.com/watch?v=QCN7wJV224A
He is building 3D Printed gears and his current project is building a robot using such gears.
The ODrive looks like this.
It has an ARM microcontroller (STM32), two motor drivers and a real bunch of mosfets to drive two motors and a power resistor.
The board layout gives you an hint that this board is able to handle a lot of power :-)
The specs are the followings:
- 24V and 48V version
- Peak current > 100A, above 30A in continuous it will need some active cooling (https://discourse.odriverobotics.com/t/motor-torque-and-temperature-measurements-for-keda-6364-motors-and-mosfet-temperature-rise/356)
- Encoder (8192 per revolution $ 39)
- Braking mode: regenerative (battery packs) or brake resistor.
- Versatile interfacing: USB, Step/Direction, UART, Servo PWM/PPM, CAN ...
- Cost effective $ 129 for 24V and $ 159 for 48 V
- RC motors are super cheap, very powerful ( $ 15 for 700W ) and they can spin really fast.
GitHub for Hardware and Software: https://github.com/madcowswe/ODrive#getting-started
The firmware seems to use FreeRTOS, STM32 libs.
HackADay: https://hackaday.io/project/11583/logs?sort=newest
There is this excellent spreadsheet that shows a characterization of several RC motors (including voltage, acceleration, braking resistor...)
https://docs.google.com/spreadsheets/d/12vzz7XVEK6YNIOqH0jAz51F5VUpc-lJEs3mmkWP1H4Y/edit#gid=0
Typically for a 3D Printer, the 24V board seems enough for even large printers and common CNC machines (up to 1Nm torque with 1KW motors), above this torque the 48V board is needed.
Video Demos:
- A relatively heavy gantry
https://youtu.be/FUh36RUHzdU - An Ultimaker style gantry using probably fish ropes instead of belts
https://youtu.be/WT4E5nb3KtY
This board allows to control high speed/power motors in a closed loop, this enables 3D Printers/CNC/Robots to move in the industrial league: control of the position/speed/acceleration/torque and also silence. The torque and the rpm can be limited at the firmware level, so you do not need large and expensive power supplies.
Pretty cool hardware !